<?php

if (! defined ( 'BASEPATH' ))
	exit ( 'No direct script access allowed' );
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 5.1.6 or newer
 *
 * @package		CodeIgniter
 * @author		ExpressionEngine Dev Team
 * @copyright	Copyright (c) 2008 - 2011, EllisLab, Inc.
 * @license		http://codeigniter.com/user_guide/license.html
 * @link		http://codeigniter.com
 * @since		Version 1.0
 * @filesource
 */

// ------------------------------------------------------------------------


/**
 * Loader Class
 *
 * Loads views and files
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @author		ExpressionEngine Dev Team
 * @category	Loader
 * @link		http://codeigniter.com/user_guide/libraries/loader.html
 */
class CI_Loader {
	
	// All these are set automatically. Don't mess with them.
	protected $_ci_ob_level;
	protected $_ci_view_paths = array ();
	protected $_ci_library_paths = array ();
	protected $_ci_model_paths = array ();
	protected $_ci_helper_paths = array ();
	protected $_base_classes = array (); // Set by the controller class
	protected $_ci_cached_vars = array ();
	protected $_ci_classes = array ();
	protected $_ci_loaded_files = array ();
	protected $_ci_models = array ();
	protected $_ci_helpers = array ();
	protected $_ci_varmap = array ('unit_test' => 'unit', 'user_agent' => 'agent' );
	
	/**
	 * Constructor
	 *
	 * Sets the path to the view files and gets the initial output buffering level
	 */
	public function __construct() {
		$this->_ci_ob_level = ob_get_level ();
		$this->_ci_library_paths = array (APPPATH, BASEPATH );
		$this->_ci_helper_paths = array (APPPATH, BASEPATH );
		$this->_ci_model_paths = array (APPPATH );
		$this->_ci_view_paths = array (APPPATH . 'views/' => TRUE );
		
		log_message ( 'debug', "Loader Class Initialized" );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Set _base_classes variable
	 *
	 * This method is called once in CI_Controller.
	 *
	 * @param 	array
	 * @return 	object
	 */
	public function set_base_classes() {
		$this->_base_classes = & is_loaded ();
		
		return $this;
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Is Loaded
	 *
	 * A utility function to test if a class is in the self::$_ci_classes array.
	 * This function returns the object name if the class tested for is loaded,
	 * and returns FALSE if it isn't.
	 *
	 * It is mainly used in the form_helper -> _get_validation_object()
	 *
	 * @param 	string	class being checked for
	 * @return 	mixed	class object name on the CI SuperObject or FALSE
	 */
	public function is_loaded($class) {
		if (isset ( $this->_ci_classes [$class] )) {
			return $this->_ci_classes [$class];
		}
		
		return FALSE;
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Class Loader
	 *
	 * This function lets users load and instantiate classes.
	 * It is designed to be called from a user's app controllers.
	 *
	 * @param	string	the name of the class
	 * @param	mixed	the optional parameters
	 * @param	string	an optional object name
	 * @return	void
	 */
	public function library($library = '', $params = NULL, $object_name = NULL) {
		if (is_array ( $library )) {
			foreach ( $library as $class ) {
				$this->library ( $class, $params );
			}
			
			return;
		}
		
		if ($library == '' or isset ( $this->_base_classes [$library] )) {
			return FALSE;
		}
		
		if (! is_null ( $params ) && ! is_array ( $params )) {
			$params = NULL;
		}
		
		$this->_ci_load_class ( $library, $params, $object_name );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Model Loader
	 *
	 * This function lets users load and instantiate models.
	 *
	 * @param	string	the name of the class
	 * @param	string	name for the model
	 * @param	bool	database connection
	 * @return	void
	 */
	public function model($model, $name = '', $db_conn = FALSE) {
		if (is_array ( $model )) {
			foreach ( $model as $babe ) {
				$this->model ( $babe );
			}
			return;
		}
		
		if ($model == '') {
			return;
		}
		
		$path = '';
		
		// Is the model in a sub-folder? If so, parse out the filename and path.
		if (($last_slash = strrpos ( $model, '/' )) !== FALSE) {
			// The path is in front of the last slash
			$path = substr ( $model, 0, $last_slash + 1 );
			
			// And the model name behind it
			$model = substr ( $model, $last_slash + 1 );
		}
		
		if ($name == '') {
			$name = $model;
		}
		
		if (in_array ( $name, $this->_ci_models, TRUE )) {
			return;
		}
		
		$CI = & get_instance ();
		if (isset ( $CI->$name )) {
			show_error ( 'The model name you are loading is the name of a resource that is already being used: ' . $name );
		}
		
		$model = strtolower ( $model );
		
		foreach ( $this->_ci_model_paths as $mod_path ) {
			if (! file_exists ( $mod_path . 'models/' . $path . $model . '.php' )) {
				continue;
			}
			
			if ($db_conn !== FALSE and ! class_exists ( 'CI_DB' )) {
				if ($db_conn === TRUE) {
					$db_conn = '';
				}
				
				$CI->load->database ( $db_conn, FALSE, TRUE );
			}
			
			if (! class_exists ( 'CI_Model' )) {
				load_class ( 'Model', 'core' );
			}
			
			require_once ($mod_path . 'models/' . $path . $model . '.php');
			
			$model = ucfirst ( $model );
			
			$CI->$name = new $model ();
			
			$this->_ci_models [] = $name;
			return;
		}
		
		// couldn't find the model
		show_error ( 'Unable to locate the model you have specified: ' . $model );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Database Loader
	 *
	 * @param	string	the DB credentials
	 * @param	bool	whether to return the DB object
	 * @param	bool	whether to enable active record (this allows us to override the config setting)
	 * @return	object
	 */
	public function database($params = '', $return = FALSE, $active_record = NULL) {
		// Grab the super object
		$CI = & get_instance ();
		
		// Do we even need to load the database class?
		if (class_exists ( 'CI_DB' ) and $return == FALSE and $active_record == NULL and isset ( $CI->db ) and is_object ( $CI->db )) {
			return FALSE;
		}
		
		require_once (BASEPATH . 'database/DB.php');
		
		if ($return === TRUE) {
			return DB ( $params, $active_record );
		}
		
		// Initialize the db variable.  Needed to prevent
		// reference errors with some configurations
		$CI->db = '';
		
		// Load the DB class
		$CI->db = & DB ( $params, $active_record );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Load the Utilities Class
	 *
	 * @return	string
	 */
	public function dbutil() {
		if (! class_exists ( 'CI_DB' )) {
			$this->database ();
		}
		
		$CI = & get_instance ();
		
		// for backwards compatibility, load dbforge so we can extend dbutils off it
		// this use is deprecated and strongly discouraged
		$CI->load->dbforge ();
		
		require_once (BASEPATH . 'database/DB_utility.php');
		require_once (BASEPATH . 'database/drivers/' . $CI->db->dbdriver . '/' . $CI->db->dbdriver . '_utility.php');
		$class = 'CI_DB_' . $CI->db->dbdriver . '_utility';
		
		$CI->dbutil = new $class ();
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Load the Database Forge Class
	 *
	 * @return	string
	 */
	public function dbforge() {
		if (! class_exists ( 'CI_DB' )) {
			$this->database ();
		}
		
		$CI = & get_instance ();
		
		require_once (BASEPATH . 'database/DB_forge.php');
		require_once (BASEPATH . 'database/drivers/' . $CI->db->dbdriver . '/' . $CI->db->dbdriver . '_forge.php');
		$class = 'CI_DB_' . $CI->db->dbdriver . '_forge';
		
		$CI->dbforge = new $class ();
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Load View
	 *
	 * This function is used to load a "view" file.  It has three parameters:
	 *
	 * 1. The name of the "view" file to be included.
	 * 2. An associative array of data to be extracted for use in the view.
	 * 3. TRUE/FALSE - whether to return the data or load it.  In
	 * some cases it's advantageous to be able to return data so that
	 * a developer can process it in some way.
	 *
	 * @param	string
	 * @param	array
	 * @param	bool
	 * @return	void
	 */
	public function view($view, $vars = array(), $return = FALSE) {
		return $this->_ci_load ( array ('_ci_view' => $view, '_ci_vars' => $this->_ci_object_to_array ( $vars ), '_ci_return' => $return ) );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Load File
	 *
	 * This is a generic file loader
	 *
	 * @param	string
	 * @param	bool
	 * @return	string
	 */
	public function file($path, $return = FALSE) {
		return $this->_ci_load ( array ('_ci_path' => $path, '_ci_return' => $return ) );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Set Variables
	 *
	 * Once variables are set they become available within
	 * the controller class and its "view" files.
	 *
	 * @param	array
	 * @return	void
	 */
	public function vars($vars = array(), $val = '') {
		if ($val != '' and is_string ( $vars )) {
			$vars = array ($vars => $val );
		}
		
		$vars = $this->_ci_object_to_array ( $vars );
		
		if (is_array ( $vars ) and count ( $vars ) > 0) {
			foreach ( $vars as $key => $val ) {
				$this->_ci_cached_vars [$key] = $val;
			}
		}
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Get Variable
	 *
	 * Check if a variable is set and retrieve it.
	 *
	 * @param	array
	 * @return	void
	 */
	public function get_var($key) {
		return isset ( $this->_ci_cached_vars [$key] ) ? $this->_ci_cached_vars [$key] : NULL;
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Load Helper
	 *
	 * This function loads the specified helper file.
	 *
	 * @param	mixed
	 * @return	void
	 */
	public function helper($helpers = array()) {
		foreach ( $this->_ci_prep_filename ( $helpers, '_helper' ) as $helper ) {
			if (isset ( $this->_ci_helpers [$helper] )) {
				continue;
			}
			
			$ext_helper = APPPATH . 'helpers/' . config_item ( 'subclass_prefix' ) . $helper . '.php';
			
			// Is this a helper extension request?
			if (file_exists ( $ext_helper )) {
				$base_helper = BASEPATH . 'helpers/' . $helper . '.php';
				
				if (! file_exists ( $base_helper )) {
					show_error ( 'Unable to load the requested file: helpers/' . $helper . '.php' );
				}
				
				include_once ($ext_helper);
				include_once ($base_helper);
				
				$this->_ci_helpers [$helper] = TRUE;
				log_message ( 'debug', 'Helper loaded: ' . $helper );
				continue;
			}
			
			// Try to load the helper
			foreach ( $this->_ci_helper_paths as $path ) {
				if (file_exists ( $path . 'helpers/' . $helper . '.php' )) {
					include_once ($path . 'helpers/' . $helper . '.php');
					
					$this->_ci_helpers [$helper] = TRUE;
					log_message ( 'debug', 'Helper loaded: ' . $helper );
					break;
				}
			}
			
			// unable to load the helper
			if (! isset ( $this->_ci_helpers [$helper] )) {
				show_error ( 'Unable to load the requested file: helpers/' . $helper . '.php' );
			}
		}
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Load Helpers
	 *
	 * This is simply an alias to the above function in case the
	 * user has written the plural form of this function.
	 *
	 * @param	array
	 * @return	void
	 */
	public function helpers($helpers = array()) {
		$this->helper ( $helpers );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Loads a language file
	 *
	 * @param	array
	 * @param	string
	 * @return	void
	 */
	public function language($file = array(), $lang = '') {
		$CI = & get_instance ();
		
		if (! is_array ( $file )) {
			$file = array ($file );
		}
		
		foreach ( $file as $langfile ) {
			$CI->lang->load ( $langfile, $lang );
		}
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Loads a config file
	 *
	 * @param	string
	 * @return	void
	 */
	public function config($file = '', $use_sections = FALSE, $fail_gracefully = FALSE) {
		$CI = & get_instance ();
		$CI->config->load ( $file, $use_sections, $fail_gracefully );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Driver
	 *
	 * Loads a driver library
	 *
	 * @param	string	the name of the class
	 * @param	mixed	the optional parameters
	 * @param	string	an optional object name
	 * @return	void
	 */
	public function driver($library = '', $params = NULL, $object_name = NULL) {
		if (! class_exists ( 'CI_Driver_Library' )) {
			// we aren't instantiating an object here, that'll be done by the Library itself
			require BASEPATH . 'libraries/Driver.php';
		}
		
		// We can save the loader some time since Drivers will *always* be in a subfolder,
		// and typically identically named to the library
		if (! strpos ( $library, '/' )) {
			$library = ucfirst ( $library ) . '/' . $library;
		}
		
		return $this->library ( $library, $params, $object_name );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Add Package Path
	 *
	 * Prepends a parent path to the library, model, helper, and config path arrays
	 *
	 * @param	string
	 * @param 	boolean
	 * @return	void
	 */
	public function add_package_path($path, $view_cascade = TRUE) {
		$path = rtrim ( $path, '/' ) . '/';
		
		array_unshift ( $this->_ci_library_paths, $path );
		array_unshift ( $this->_ci_model_paths, $path );
		array_unshift ( $this->_ci_helper_paths, $path );
		
		$this->_ci_view_paths = array ($path . 'views/' => $view_cascade ) + $this->_ci_view_paths;
		
		// Add config file path
		$config = & $this->_ci_get_component ( 'config' );
		array_unshift ( $config->_config_paths, $path );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Get Package Paths
	 *
	 * Return a list of all package paths, by default it will ignore BASEPATH.
	 *
	 * @param	string
	 * @return	void
	 */
	public function get_package_paths($include_base = FALSE) {
		return $include_base === TRUE ? $this->_ci_library_paths : $this->_ci_model_paths;
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Remove Package Path
	 *
	 * Remove a path from the library, model, and helper path arrays if it exists
	 * If no path is provided, the most recently added path is removed.
	 *
	 * @param	type
	 * @return	type
	 */
	public function remove_package_path($path = '', $remove_config_path = TRUE) {
		$config = & $this->_ci_get_component ( 'config' );
		
		if ($path == '') {
			$void = array_shift ( $this->_ci_library_paths );
			$void = array_shift ( $this->_ci_model_paths );
			$void = array_shift ( $this->_ci_helper_paths );
			$void = array_shift ( $this->_ci_view_paths );
			$void = array_shift ( $config->_config_paths );
		} else {
			$path = rtrim ( $path, '/' ) . '/';
			foreach ( array ('_ci_library_paths', '_ci_model_paths', '_ci_helper_paths' ) as $var ) {
				if (($key = array_search ( $path, $this->{$var} )) !== FALSE) {
					unset ( $this->{$var} [$key] );
				}
			}
			
			if (isset ( $this->_ci_view_paths [$path . 'views/'] )) {
				unset ( $this->_ci_view_paths [$path . 'views/'] );
			}
			
			if (($key = array_search ( $path, $config->_config_paths )) !== FALSE) {
				unset ( $config->_config_paths [$key] );
			}
		}
		
		// make sure the application default paths are still in the array
		$this->_ci_library_paths = array_unique ( array_merge ( $this->_ci_library_paths, array (APPPATH, BASEPATH ) ) );
		$this->_ci_helper_paths = array_unique ( array_merge ( $this->_ci_helper_paths, array (APPPATH, BASEPATH ) ) );
		$this->_ci_model_paths = array_unique ( array_merge ( $this->_ci_model_paths, array (APPPATH ) ) );
		$this->_ci_view_paths = array_merge ( $this->_ci_view_paths, array (APPPATH . 'views/' => TRUE ) );
		$config->_config_paths = array_unique ( array_merge ( $config->_config_paths, array (APPPATH ) ) );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Loader
	 *
	 * This function is used to load views and files.
	 * Variables are prefixed with _ci_ to avoid symbol collision with
	 * variables made available to view files
	 *
	 * @param	array
	 * @return	void
	 */
	protected function _ci_load($_ci_data) {
		// Set the default data variables
		foreach ( array ('_ci_view', '_ci_vars', '_ci_path', '_ci_return' ) as $_ci_val ) {
			$$_ci_val = (! isset ( $_ci_data [$_ci_val] )) ? FALSE : $_ci_data [$_ci_val];
		}
		
		$file_exists = FALSE;
		
		// Set the path to the requested file
		if ($_ci_path != '') {
			$_ci_x = explode ( '/', $_ci_path );
			$_ci_file = end ( $_ci_x );
		} else {
			$_ci_ext = pathinfo ( $_ci_view, PATHINFO_EXTENSION );
			$_ci_file = ($_ci_ext == '') ? $_ci_view . '.php' : $_ci_view;
			
			foreach ( $this->_ci_view_paths as $view_file => $cascade ) {
				if (file_exists ( $view_file . $_ci_file )) {
					$_ci_path = $view_file . $_ci_file;
					$file_exists = TRUE;
					break;
				}
				
				if (! $cascade) {
					break;
				}
			}
		}
		
		if (! $file_exists && ! file_exists ( $_ci_path )) {
			show_error ( 'Unable to load the requested file: ' . $_ci_file );
		}
		
		// This allows anything loaded using $this->load (views, files, etc.)
		// to become accessible from within the Controller and Model functions.
		

		$_ci_CI = & get_instance ();
		foreach ( get_object_vars ( $_ci_CI ) as $_ci_key => $_ci_var ) {
			if (! isset ( $this->$_ci_key )) {
				$this->$_ci_key = & $_ci_CI->$_ci_key;
			}
		}
		
		/*
		 * Extract and cache variables
		 *
		 * You can either set variables using the dedicated $this->load_vars()
		 * function or via the second parameter of this function. We'll merge
		 * the two types and cache them so that views that are embedded within
		 * other views can have access to these variables.
		 */
		if (is_array ( $_ci_vars )) {
			$this->_ci_cached_vars = array_merge ( $this->_ci_cached_vars, $_ci_vars );
		}
		extract ( $this->_ci_cached_vars );
		
		/*
		 * Buffer the output
		 *
		 * We buffer the output for two reasons:
		 * 1. Speed. You get a significant speed boost.
		 * 2. So that the final rendered template can be
		 * post-processed by the output class.  Why do we
		 * need post processing?  For one thing, in order to
		 * show the elapsed page load time.  Unless we
		 * can intercept the content right before it's sent to
		 * the browser and then stop the timer it won't be accurate.
		 */
		ob_start ();
		
		// If the PHP installation does not support short tags we'll
		// do a little string replacement, changing the short tags
		// to standard PHP echo statements.
		

		if (( bool ) @ini_get ( 'short_open_tag' ) === FALSE and config_item ( 'rewrite_short_tags' ) == TRUE) {
			echo eval ( '?>' . preg_replace ( "/;*\s*\?>/", "; ?>", str_replace ( '<?=', '<?php echo ', file_get_contents ( $_ci_path ) ) ) );
		} else {
			include ($_ci_path); // include() vs include_once() allows for multiple views with the same name
		}
		
		log_message ( 'debug', 'File loaded: ' . $_ci_path );
		
		// Return the file data if requested
		if ($_ci_return === TRUE) {
			$buffer = ob_get_contents ();
			@ob_end_clean ();
			return $buffer;
		}
		
		/*
		 * Flush the buffer... or buff the flusher?
		 *
		 * In order to permit views to be nested within
		 * other views, we need to flush the content back out whenever
		 * we are beyond the first level of output buffering so that
		 * it can be seen and included properly by the first included
		 * template and any subsequent ones. Oy!
		 *
		 */
		if (ob_get_level () > $this->_ci_ob_level + 1) {
			ob_end_flush ();
		} else {
			$_ci_CI->output->append_output ( ob_get_contents () );
			@ob_end_clean ();
		}
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Load class
	 *
	 * This function loads the requested class.
	 *
	 * @param	string	the item that is being loaded
	 * @param	mixed	any additional parameters
	 * @param	string	an optional object name
	 * @return	void
	 */
	protected function _ci_load_class($class, $params = NULL, $object_name = NULL) {
		// Get the class name, and while we're at it trim any slashes.
		// The directory path can be included as part of the class name,
		// but we don't want a leading slash
		$class = str_replace ( '.php', '', trim ( $class, '/' ) );
		
		// Was the path included with the class name?
		// We look for a slash to determine this
		$subdir = '';
		if (($last_slash = strrpos ( $class, '/' )) !== FALSE) {
			// Extract the path
			$subdir = substr ( $class, 0, $last_slash + 1 );
			
			// Get the filename from the path
			$class = substr ( $class, $last_slash + 1 );
		}
		
		// We'll test for both lowercase and capitalized versions of the file name
		foreach ( array (ucfirst ( $class ), strtolower ( $class ) ) as $class ) {
			$subclass = APPPATH . 'libraries/' . $subdir . config_item ( 'subclass_prefix' ) . $class . '.php';
			
			// Is this a class extension request?
			if (file_exists ( $subclass )) {
				$baseclass = BASEPATH . 'libraries/' . ucfirst ( $class ) . '.php';
				
				if (! file_exists ( $baseclass )) {
					log_message ( 'error', "Unable to load the requested class: " . $class );
					show_error ( "Unable to load the requested class: " . $class );
				}
				
				// Safety:  Was the class already loaded by a previous call?
				if (in_array ( $subclass, $this->_ci_loaded_files )) {
					// Before we deem this to be a duplicate request, let's see
					// if a custom object name is being supplied.  If so, we'll
					// return a new instance of the object
					if (! is_null ( $object_name )) {
						$CI = & get_instance ();
						if (! isset ( $CI->$object_name )) {
							return $this->_ci_init_class ( $class, config_item ( 'subclass_prefix' ), $params, $object_name );
						}
					}
					
					$is_duplicate = TRUE;
					log_message ( 'debug', $class . " class already loaded. Second attempt ignored." );
					return;
				}
				
				include_once ($baseclass);
				include_once ($subclass);
				$this->_ci_loaded_files [] = $subclass;
				
				return $this->_ci_init_class ( $class, config_item ( 'subclass_prefix' ), $params, $object_name );
			}
			
			// Lets search for the requested library file and load it.
			$is_duplicate = FALSE;
			foreach ( $this->_ci_library_paths as $path ) {
				$filepath = $path . 'libraries/' . $subdir . $class . '.php';
				
				// Does the file exist?  No?  Bummer...
				if (! file_exists ( $filepath )) {
					continue;
				}
				
				// Safety:  Was the class already loaded by a previous call?
				if (in_array ( $filepath, $this->_ci_loaded_files )) {
					// Before we deem this to be a duplicate request, let's see
					// if a custom object name is being supplied.  If so, we'll
					// return a new instance of the object
					if (! is_null ( $object_name )) {
						$CI = & get_instance ();
						if (! isset ( $CI->$object_name )) {
							return $this->_ci_init_class ( $class, '', $params, $object_name );
						}
					}
					
					$is_duplicate = TRUE;
					log_message ( 'debug', $class . " class already loaded. Second attempt ignored." );
					return;
				}
				
				include_once ($filepath);
				$this->_ci_loaded_files [] = $filepath;
				return $this->_ci_init_class ( $class, '', $params, $object_name );
			}
		
		} // END FOREACH
		

		// One last attempt.  Maybe the library is in a subdirectory, but it wasn't specified?
		if ($subdir == '') {
			$path = strtolower ( $class ) . '/' . $class;
			return $this->_ci_load_class ( $path, $params );
		}
		
		// If we got this far we were unable to find the requested class.
		// We do not issue errors if the load call failed due to a duplicate request
		if ($is_duplicate == FALSE) {
			log_message ( 'error', "Unable to load the requested class: " . $class );
			show_error ( "Unable to load the requested class: " . $class );
		}
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Instantiates a class
	 *
	 * @param	string
	 * @param	string
	 * @param	string	an optional object name
	 * @return	null
	 */
	protected function _ci_init_class($class, $prefix = '', $config = FALSE, $object_name = NULL) {
		// Is there an associated config file for this class?  Note: these should always be lowercase
		if ($config === NULL) {
			// Fetch the config paths containing any package paths
			$config_component = $this->_ci_get_component ( 'config' );
			
			if (is_array ( $config_component->_config_paths )) {
				// Break on the first found file, thus package files
				// are not overridden by default paths
				foreach ( $config_component->_config_paths as $path ) {
					// We test for both uppercase and lowercase, for servers that
					// are case-sensitive with regard to file names. Check for environment
					// first, global next
					if (defined ( 'ENVIRONMENT' ) and file_exists ( $path . 'config/' . ENVIRONMENT . '/' . strtolower ( $class ) . '.php' )) {
						include_once ($path . 'config/' . ENVIRONMENT . '/' . strtolower ( $class ) . '.php');
						break;
					} elseif (defined ( 'ENVIRONMENT' ) and file_exists ( $path . 'config/' . ENVIRONMENT . '/' . ucfirst ( strtolower ( $class ) ) . '.php' )) {
						include_once ($path . 'config/' . ENVIRONMENT . '/' . ucfirst ( strtolower ( $class ) ) . '.php');
						break;
					} elseif (file_exists ( $path . 'config/' . strtolower ( $class ) . '.php' )) {
						include_once ($path . 'config/' . strtolower ( $class ) . '.php');
						break;
					} elseif (file_exists ( $path . 'config/' . ucfirst ( strtolower ( $class ) ) . '.php' )) {
						include_once ($path . 'config/' . ucfirst ( strtolower ( $class ) ) . '.php');
						break;
					}
				}
			}
		}
		
		if ($prefix == '') {
			if (class_exists ( 'CI_' . $class )) {
				$name = 'CI_' . $class;
			} elseif (class_exists ( config_item ( 'subclass_prefix' ) . $class )) {
				$name = config_item ( 'subclass_prefix' ) . $class;
			} else {
				$name = $class;
			}
		} else {
			$name = $prefix . $class;
		}
		
		// Is the class name valid?
		if (! class_exists ( $name )) {
			log_message ( 'error', "Non-existent class: " . $name );
			show_error ( "Non-existent class: " . $class );
		}
		
		// Set the variable name we will assign the class to
		// Was a custom class name supplied?  If so we'll use it
		$class = strtolower ( $class );
		
		if (is_null ( $object_name )) {
			$classvar = (! isset ( $this->_ci_varmap [$class] )) ? $class : $this->_ci_varmap [$class];
		} else {
			$classvar = $object_name;
		}
		
		// Save the class name and object name
		$this->_ci_classes [$class] = $classvar;
		
		// Instantiate the class
		$CI = & get_instance ();
		if ($config !== NULL) {
			$CI->$classvar = new $name ( $config );
		} else {
			$CI->$classvar = new $name ();
		}
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Autoloader
	 *
	 * The config/autoload.php file contains an array that permits sub-systems,
	 * libraries, and helpers to be loaded automatically.
	 *
	 * This function is public, as it's used in the CI_Controller class.
	 * However, there is no reason you should ever needs to use it.
	 *
	 * @param	array
	 * @return	void
	 */
	public function ci_autoloader() {
		if (defined ( 'ENVIRONMENT' ) and file_exists ( APPPATH . 'config/' . ENVIRONMENT . '/autoload.php' )) {
			include_once (APPPATH . 'config/' . ENVIRONMENT . '/autoload.php');
		} else {
			include_once (APPPATH . 'config/autoload.php');
		}
		
		if (! isset ( $autoload )) {
			return FALSE;
		}
		
		// Autoload packages
		if (isset ( $autoload ['packages'] )) {
			foreach ( $autoload ['packages'] as $package_path ) {
				$this->add_package_path ( $package_path );
			}
		}
		
		// Load any custom config file
		if (count ( $autoload ['config'] ) > 0) {
			$CI = & get_instance ();
			foreach ( $autoload ['config'] as $key => $val ) {
				$CI->config->load ( $val );
			}
		}
		
		// Autoload helpers and languages
		foreach ( array ('helper', 'language' ) as $type ) {
			if (isset ( $autoload [$type] ) and count ( $autoload [$type] ) > 0) {
				$this->$type ( $autoload [$type] );
			}
		}
		
		// A little tweak to remain backward compatible
		// The $autoload['core'] item was deprecated
		if (! isset ( $autoload ['libraries'] ) and isset ( $autoload ['core'] )) {
			$autoload ['libraries'] = $autoload ['core'];
		}
		
		// Load libraries
		if (isset ( $autoload ['libraries'] ) and count ( $autoload ['libraries'] ) > 0) {
			// Load the database driver.
			if (in_array ( 'database', $autoload ['libraries'] )) {
				$this->database ();
				$autoload ['libraries'] = array_diff ( $autoload ['libraries'], array ('database' ) );
			}
			
			// Load all other libraries
			foreach ( $autoload ['libraries'] as $item ) {
				$this->library ( $item );
			}
		}
		
		// Autoload models
		if (isset ( $autoload ['model'] )) {
			$this->model ( $autoload ['model'] );
		}
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Object to Array
	 *
	 * Takes an object as input and converts the class variables to array key/vals
	 *
	 * @param	object
	 * @return	array
	 */
	protected function _ci_object_to_array($object) {
		return (is_object ( $object )) ? get_object_vars ( $object ) : $object;
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Get a reference to a specific library or model
	 *
	 * @return	bool
	 */
	protected function &_ci_get_component($component) {
		$CI = & get_instance ();
		return $CI->$component;
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Prep filename
	 *
	 * This function preps the name of various items to make loading them more reliable.
	 *
	 * @param	mixed
	 * @return	array
	 */
	protected function _ci_prep_filename($filename, $extension) {
		if (! is_array ( $filename )) {
			return array (strtolower ( str_replace ( '.php', '', str_replace ( $extension, '', $filename ) ) . $extension ) );
		} else {
			foreach ( $filename as $key => $val ) {
				$filename [$key] = strtolower ( str_replace ( '.php', '', str_replace ( $extension, '', $val ) ) . $extension );
			}
			
			return $filename;
		}
	}
}

/* End of file Loader.php */
/* Location: ./system/core/Loader.php */